Communicating with the HP 3421A Data Aquisition/Control Unit

[Danilo C.]

Hello everyone. I am not an HP antiques enthusiast, but it has come to be that I must use an HP 3421A in a project I'm participating in.

I am looking for a way to use the HP 3421A without the HP calculators/computers I know it was made to be used with. However, since the material on this piece of technology is pretty scarce, i have not been able to find a straightforward way of doing so. Therefore, I came here to see if any of you know of what i might need to do so.

I have found a user manual for the device, but it has not been very useful in showing me the way, or so to say.

Anything you all may show me will be helpful.

[rprosperi]

I don't believe this standard, HP-IL based device is of any use at all without an HP-IL Controller (HP-41, HP-75C, HP-71B or HP-110/Portable Plus) as even though it has a small display, what is shown there is managed by the external controller.

There was also an optional HP-IB interface available for this, but again you would need an external controller computer.

What are you trying to use it for?

[KeithB]

As rprosperi says, you really need a computer of some kind for this.

If it has the GPIB interface, you can get a USB-GPIB interface and use a PC to control it.

You could also get a GPIB->HPIL interface - which are very rare.

Would a PIL-Box allow him to communicate with it?

[born2laser]

(07-26-2024 02:07 PM)KeithB Wrote:  As rprosperi says, you really need a computer of some kind for this.

If it has the GPIB interface, you can get a USB-GPIB interface and use a PC to control it.

You could also get a GPIB->HPIL interface - which are very rare.

Would a PIL-Box allow him to communicate with it?

I think a PIL-Box would do the trick for you, not sure if any of the existing software would work as is, but it is stuff you can do on a PC using any of many tools, I personally would use Labview.
Now the next problem, PIL-Boxes are hard to come by nowadays

Juan

[KeithB]

"PIL-Boxes are hard to come by nowadays"
Probably easier than an HPIB->HPIL converter!

[Dave Frederickson]

(07-26-2024 02:07 PM)KeithB Wrote:  Would a PIL-Box allow him to communicate with it?

Yes! Emu71 can communicate with the 3421A through the PIL-Box just fine. Additionally, the Data Acq ROM can be installed in Emu71.

[Garth Wilson]

(07-26-2024 09:55 PM)Dave Frederickson Wrote:  

(07-26-2024 02:07 PM)KeithB Wrote:  Would a PIL-Box allow him to communicate with it?

Yes! Emu71 can communicate with the 3421A through the PIL-Box just fine. Additionally, the Data Acq ROM can be installed in Emu71.

Note however that the special ROM is not mandatory; it might only make your program a little easier and more compact.  The instruction language of the 3421A is plenty simple, and I used it extensively with a 41cx with HP-IL and XIO, with no data-acquisition ROM.  I think I was mostly done using the 3421A when I got into the 71.

[Dave Frederickson]

(07-26-2024 10:26 PM)Garth Wilson Wrote:  Note however that the special ROM is not mandatory; it might only make your program a little easier and more compact. 

I think you might be selling the Data Acq ROM short.
At 64k, the Data Acq ROM is the largest application ROM for the 71B. The large-format manual is 233 pages long. And the ROM includes an overlay which can be installed into Emu71. That's quite a lot of baggage for a ROM that "makes the programming a little easier and more compact". Finally, it costs nothing to install the ROM into Emu71.

Edit: An article highlighting the features of the Data Acq ROM can be found in the March 1986 edition of the HP Journal.

http://hparchive.com/Journals/HPJ-1986-03.pdf

[Dave Frederickson]

A couple of questions ...

Do you have the modules and connectors you need for the 3421A?
Do you require the accuracy of a calibrated unit? If so, is the Calibration RAM battery good?

Just curious.

[Garth Wilson]

Dave, the file does not open here.  I do not have trouble with .pdf's, but my document viewer says this one is plain text and doesn't support it, and the text editor says it's empty and it just shows a blank page.  Anyway, I haven't seen the manual, but the 3421A is simple enough to use that I can hardly imagine what a 64KB ROM is needed for.

[Dave Frederickson]

(07-27-2024 02:45 AM)Garth Wilson Wrote:  Dave, the file does not open here.  I do not have trouble with .pdf's, but my document viewer says this one is plain text and doesn't support it, and the text editor says it's empty and it just shows a blank page.  Anyway, I haven't seen the manual, but the 3421A is simple enough to use that I can hardly imagine what a 64KB ROM is needed for.

What file? If you mean the HP Journal then just download it from somewhere else. I would have linked to the file at hpmuseum.net but for the past couple of days it appears to be down.

Yes, the 3421A is simple to use, but it's capabilities are beyond your imagination. Are you familiar with the 3056DL Data Logger System?

[Garth Wilson]

(07-27-2024 06:03 AM)Dave Frederickson Wrote:  Yes, the 3421A is simple to use, but its capabilities are beyond your imagination. Are you familiar with the 3056DL Data Logger System?

I'm not familiar with the 3056DL except that I'm looking at it in an HP brochure I kept from 35+ years ago.  I used the 3421A at work with two or three modules that plugged into the back for relays and digital I/O to control signal routing and control a couple of other in-house-made pieces of equipment in our test setup, in addition to its DMM functions of course.

[vassilisprevelakis]

(07-26-2024 02:07 PM)KeithB Wrote:  You could also get a GPIB->HPIL interface - which are very rare.

hi,

if I remember correctly, every HP 2225A thinkjet has an GPIB->HPIL interface inside it.

**vp

http://www.series80.org

[KeithB]

(07-28-2024 05:43 PM)vassilisprevelakis Wrote:  

(07-26-2024 02:07 PM)KeithB Wrote:  You could also get a GPIB->HPIL interface - which are very rare.

hi,

if I remember correctly, every HP 2225A thinkjet has an GPIB->HPIL interface inside it.

**vp

http://www.series80.org

This would require an HPIL controller, so a standard GPIB interface would probably be required.

[Dave Frederickson]

(07-28-2024 09:51 PM)KeithB Wrote:  This would require an HPIL controller, so a standard GPIB interface would probably be required.

I don't see a GPIB adapter being a viable solution as I doubt a LabVIEW driver exists for the 3421A.

Being able to transition from the virtual 71B and a PIL-Box to a physical 71B and portability seems to be a desirable capability.

[KeithB]

What is so special about a LabView driver?

I would use the .net NI488 device class that lets me talk to the instrument directly.
(Of course, if I was using the PIL-Box, I would abstract it to make it *look* like the NI488 device.)

You just send the text command to the 3421A, and parse the response you get back.

But it looks like we scared the OP off, or he thought better of it and got a modern DAQ.

[born2laser]

(08-01-2024 04:11 PM)KeithB Wrote:  But it looks like we scared the OP off, or he thought better of it and got a modern DAQ.

You are probably right, but it turns out that we may have been wasting bandwidth on the discussion. I looked in J-F's web page and he anticipated this application of the PIL-Box and even supplies a Visual BASIC example for the user to build their own code (or in C++ by Christoph)

"ILCtrl is a demonstrator of a simple HP-IL controller using the PIL-Box"

http://www.jeffcalc.hp41.eu/hpil/

[KeithB]

Just for the record, and I reiterate that it is totally not necessary. (I have *never* used a LabView driver in 40 years of GPIB instrument control) but there is a LV driver for the 3421A:
https://sine.ni.com/apps/utf8/niid_web_d...0020E74861

[Dave Frederickson]

(08-07-2024 02:42 PM)KeithB Wrote:  Just for the record, and I reiterate that it is totally not necessary. (I have *never* used a LabView driver in 40 years of GPIB instrument control) but there is a LV driver for the 3421A:
https://sine.ni.com/apps/utf8/niid_web_d...0020E74861

I'm surprised. I suppose I'll now see if I can get it to work.